title: Enhancement of lanthanide evaporation by complexation: dysprosium tri-iodide mixed with indium iodide and thulium tri-iodide mixed with thallium iodide.
abstract: The vapors in equilibrium with condensates of DyI3, DyI3/InI, TmI3, and TmI3/TlI were observed over the temperature range from 900 K to 1400 K using x-ray induced fluorescence. The total densities of each element (Dy, Tm, In, Tl, and I) in the vapor, summed over all atomic and molecular species, were determined. Dramatic enhancements in the total vapor densities of Dy and Tm were observed in the vapors over DyI3/InI and TmI3/TlI as compared to the vapors over pure DyI3 and pure TmI3, respectively. An enhancement factor exceeding 10 was observed for Dy at T ≈ 1020 K, decreasing to 0 at T ≈ 1250 K. An enhancement factor exceeding 20 was observed for Tm at T ≈ 1040 K, decreasing to 0 at T ≈ 1300 K. Such enhancements are expected from the formation of the vapor-phase hetero-complexes DyInI4 and TmTlI4. Numerical simulations of the thermo-chemical equilibrium suggest the importance of additional complexes in liquid phases. A description of the measurement technique is given. Improvements in the absolute calibration lead to an approximately 40% correction to previously reported preliminary results [J. J. Curry et al., Chem. Phys. Lett. 507, 52 (2011); Appl. Phys. Lett. 100, 083505 (2012)].
authors.affiliation: National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Curry
authors.forename: E G
authors.initials: EG
authors.lastname: Estupiñán
authors.forename: A
authors.initials: A
authors.lastname: Henins
authors.forename: W P
authors.initials: WP
authors.lastname: Lapatovich
authors.forename: S D
authors.initials: SD
authors.lastname: Shastri
authors.forename: J E
authors.initials: JE
authors.lastname: Hardis